Flowmeter

ABSTRACT

A gas flowmeter which is disposed between adjacent sections of a gas piping includes a central elongate housing. This housing includes a central gas passage, a plurality of sensor modules arranged in a row adjacent the central passage, and a distribution strip arranged along the sensor modules to conduct measuring signals therefrom. A plurality of electronic processing units are mounted about the elongate housing and in electrical contact with the distribution strip to process the signals from the modules and to then produce processed signals. These processing units are shell shaped with an open longitudinal side so as to fit onto and about a corresponding portion of the elongate housing. With this construction, a compact, lightweight and easy to repair gas flowmeter is provided.

BACKGROUND OF THE INVENTION

The invention relates to a gas flowmeter of the kind where the sensor ismade by a core or central housing containing the flow-sensors and theelectronics for registration of the flow-measurement results, and thecore is placed symmetrically with an inlet and an outlet tube in anaxially symmetric line.

It is normal today to use gas meters for households that have relativelarge dimensions. This means that it can be difficult to place the meterin a convenient place for the user, particularly where interiordecoration has to be considered. Furthermore, the installation of thesemeters is very difficult, partly due to the weight and partly due to thetubes for inlet and outlet to the meters. This tubing often demands manybends close to the meter.

A more compact gas meter than the above mentioned is among others knownby U.S. Pat. No. 4,484,479. This meter is designed for axial mounting ina tube system, and contains a core with flow sensors for registration ofgas flow and electronics for registration of the results. This knownmeter has the drawback that it is difficult to adjust and repair, sinceit is necessary to demount the meter from the tube system in which it isplaced to do so.

A somewhat similar flowmeter is known from wopaper no. Wo 87/00917. Inthis meter, the sensors and the electronics are placed on a common filmsubstrate which is encapsulated in two part housing. This means that theelectronics are isolated from the sensors.

SUMMARY OF THE INVENTION

The object of the invention is to provide a gas flowmeter which iscompact and easy to install, and which at the same time is easy toadjust and repair.

This object is obtained by the meter described hereinbelow by placingone or more sensor modules in the core or central housing, together witha distribution strip. On the outside of the core is placed shell-modulesfor the electronics.

The flowmeter is characterized by its structure of minimized modules forsensors and electronics, which become a part of the tube system. Thesystem is placed in the direction of the tube, and its dimension andplacement is an extension of the tube. The measurement of theconsumption takes place on a straight line of the tube, on the way ofthe tube to the place of consumption.

On the basis of the newest technology, it is possible to reduce themodules of the measurement system and the electronic modules. It is theconstruction of these in a few well defined units that makes the metereasy to produce, program, and repair, even on location where the moduleunder consideration is replaced. This also makes other combinationspossible, by means of measuring modules used for other purposes.

The dimension of the core tube is reduced with respect to the maximumcapacity and the maximum flow speed of the meter, which again relates tothe capacity of the supply tube in such a way that the dimension of thecore is less than the dimension of supply tube. This difference is usedfor placing the sensors and the electronics in order to optimize theconstruction.

The sensors are snapped into the core, where they are sitting in linewith respect to the axial direction of the meter.

The electronics form the outer shell which is placed in the axialdirection of the core in such a way that the meter forms an extension ofthe thickness of the tube.

The placing of the meter is no problem since it is a part of the tubing,which makes it very flexible to mount.

The meter has a separate display. This makes use of the gas flowmeterfurther flexible, as it can be placed at inaccessible places where it isnot possible to read the meter. The display can then be placed in thebest place.

There is no need for a separate suspension of the meter, due to theconstruction and low weight of the meter.

Since the inlet and outlet of the meter are placed in the axialdirection, a very simple connection is achieved and the difficultmounting, and use of extensive tubing of prior meters are avoided.

The thickness of the meter is defined by the consumption, and the lengthby the number of measurements.

The entire construction makes the meter suitable for mass production byassembling, storage, packing and distribution.

The sensor and electronic modules can be placed in different orderdepending on the purpose.

This means that the sensors and the electronics are easily taken apartdue to the easy removal of the distribution strip. It is therefore notnecessary to separate the meter from the installation in order to changeand/or repair the sensors and the electronics. This construction is alsovery suitable for placing a read-out display remote to the meterinstallation. The meter is, due to its modulized construction, also verysuitable for mass-production assembling, storing, packing anddistribution.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will hereafter be explained with reference to the drawingsin which:

FIG. 1 shows the gas flowmeter in exploded view, and

FIG. 2 shows an assembled gas flowmeter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, the gas flowmeter consists of a core or centralhosing (1) with a hole therethrough for gas transportation. In each endof the core is placed a connection fitting (1a) for axial connection ofthe core to the tube system. The tube system is fitted with acorresponding connection ring (5) for connection to the fitting (la) ofthe core together with O-ring (7) and washer (8). After the connection,the connection points are sealed by a sealing ring (6) so unauthorizedoperation is prevented. FIG. 1 also shows that in core (1) are placedsensors and contact modules (2), such as temperature and pressuresensors. These modules are snapped into the core (1). In the shownexample, the contact modules (2a) are placed in each end of the sensormodules and are equipped with a hole which matches with a hole in thecore (1) for a cable connection.,

Inside the core (1) there is, beside the sensor and contact modules, aplace for a distribution strip (3) which makes the electrical connectionbetween sensor modules (2) and the electronic shell modules (4)discussed below. This strip receives current and distributes it to theshells 4 and the sensors 2. It distributes the impulses or signals fromthe sensors 2 to the shells 4, and from the shells to a remote displayor the gas plant. The contact points 3a, from strip 3, extending throughthe core 1 to shells 4, are snapped in place. The electronics in theshells are molded.

The electronic shell modules (4) are constructed in such a way that theycan be snapped onto the core (1) so that there is electrical contactwith the distribution strip (3), and thereby with the sensor and contactmodules (2).

The figure shows 3 electronic shells, the first shell (4a) is used forsafety surveillance, the second shell (4b) is used for conversion of themeasurement results, and the third (4c) is used for communication withthe complete meter. The shells are produced so the electronics aremolded in a tight material. As an example of the shell functions, thesafety module will supply a signal when there is an abnormalconsumption, in case of fire, earthquake, or a power supply failure andthereby cause a disconnection of the gas supply. The measurement shellregisters and computes the measured values, and transmits the values toa display. This module is also able to store the measured values in caseof power failure.

The communication shell will communicate with the gas plant for remoteregistration, and will also be able to receive messages from the gasplant such as for price regulation or disconnection of the supply.

The meter is connected to the tubes by connection fittings 5 which areformed as a combined telescopic/quick fixing in order to absorb sometolerances in an old installation. The connection forms a burglar prooflocking ring. In the shown version, there is mentioned 3 shells, butthis could be more or less for other applications. It would also bepossible to have other relevant measurements or the like to take placeinside or outside the shells.

The shown example shows 3 shells, but there will be no limitation withinthe limits of the invention to the numbers of shells. The externaldesign of the meter can be different to the shown design, i.e. round orsquared.

I claim:
 1. A gas-flow meter which is disposed between adjacent sections of a straight portion of a gas piping having a piping longitudinal axis comprising:a central elongate housing which is connected between the adjacent sections of the piping and which is symmetrically located about a plane including the longitudinal axis of the piping, said elongate housing including therein a central gas passage about the longitudinal axis, a plurality of sensor modules arranged in a row adjacent said central passage which are adapted to measure characteristics of a gas flowing in the gas piping including flow and to generate measuring signals indicative of the measured characteristics, and a distribution strip which is arranged along said plurality of sensor modules in electrical contact therewith upon engagement with said sensor modules such that said distribution strip serves to conduct the measuring signals of said sensor modules; and a plurality of electronic processing units mounted about said elongate housing and in electrical contact with said distribution strip whereby the measuring signals conducted from said sensor modules are processed and processed signals from said units are thus produced, said units being shell shaped with an open longitudinal side so as to fit onto and about a corresponding portion of said elongate housing and make electrical contact with said distributor strip upon being fit onto said housing.
 2. A gas-flow meter as claimed in claim 1 wherein said elongate housing is shaped in radial cross section so as to have opposed legs, said elongate housing including an opening along a length thereof between said legs which is also along said open longitudinal sides of said processing units such that through said opening is received said row of sensor modules and said distribution strip with said row of sensor modules disposed between said central gas passage and said distribution strip.
 3. A gas-flow meter as claimed in claim 2 wherein said electronic processing units have a thickness dimension all of which are all equal, and which thickness dimension is equal to an outer dimension of the piping.
 4. A gas-flow meter as claimed in claim 3 wherein said central gas passage includes an inlet at one end of said passage located symmetrically about said longitudinal axis and an outlet at the other end of said passage located symmetrically about said longitudinal axis.
 5. A gas-flow meter as claimed in claim 1 and further including a connecting means for connecting said elongate housing at each end thereof to an adjacent section of the gas piping and for suspending said elongate housing and mounted processing units from the gas piping.
 6. A gas-flow meter as claimed in claim 1 wherein the processed signals form said units are conducted to said distribution strip; and further including a cable connected to said distribution strip for supplying electrical power thereto and for relaying the processed signals to a remote location.
 7. A gas-flow meter as claimed in claim 6 wherein said distribution strip distributes electrical power to at least one of said sensor modules.
 8. A gas-flow meter as claimed in claim 1 and further including a snap connection means for electrically connecting said processing units and said distribution strip as said processing units are mounted to said elongate housing. 